Method and Apparatus for Generation and Augmentation of Search Terms from External and Internal Sources

ABSTRACT

A method and apparatus to identify names, personalities, titles, and topics that are present in a repository, and place them into a grammar, and to identify names, personalities, titles, and topics that are not present in the repository, and place them into a grammar, uses information from external data sources, notably the text used in non-speech, text-based searches, to expand the search terms entered into the ASR grammars. The expansion takes place in two forms: (1) finding plausible linguistic variants of existing search terms that are already comprehended in the repository, but that are present under slightly different names; and (2) expanding the existing search term list with items that should be there by virtue of their currency in popular culture, but which for whatever reason have not yet been reflected with content items in the repository.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent application Ser. No. 10/699,543, filed Oct. 30, 2003, which claims priority to U.S. provisional patent application Ser. No. 60/422,561, filed Oct. 31, 2002, each of which is incorporated herein in its entirety by this reference thereto.

BACKGROUND OF THE INVENTION

1. Technical Field

The invention relates to speech recognition and speech directed device control. More particularly, the invention relates to a method and apparatus for the generation and augmentation of search terms from external and internal sources, in connection with speech recognition and speech directed device control.

2. Description of the Prior Art

One area of technical innovation is that of navigation of content by spoken and textual command. Such systems typically perform speech recognition by use of a grammar-based ASR (automatic speech recognition) system, where the grammar defines those terms that can be recognized. In such systems, navigated content is comprised of a catalog, content data base, or other repository, for example: currently airing broadcast TV programs, contents of a video-on-demand (VOD) system, a catalog of cell phone ring tones, a catalog of songs, or a catalog of games. Hereafter all of the above sources of content are referred to as a repository.

Content sources are updated and/or expanded on occasion, possibly periodically, possibly as frequently as daily. In some such applications as those described above, content sources are assumed, by both system architects and by system users, to reflect trends and interests in popular culture. However, known recognition systems are limited to recognition of only those phrases that are listed in grammar. Nonetheless, it is desirable to make content sources searchable by names of artists, popular topics, personalities, etc. Yet known ASR systems recognize only those elements that are listed in grammar.

It would be desirable to identify names, personalities, titles, and topics that are present in a repository, and place them into a grammar. It would also be desirable to identify names, personalities, titles, and topics that are not present in the repository, and place them into a grammar; for in this way, such names, personalities, titles and topics may at least be recognized by the ASR system, which can then report that no suitable content is present in the repository.

SUMMARY OF THE INVENTION

The presently preferred embodiment of the invention provides a method and apparatus to identify names, personalities, titles, and topics that are present in a repository, and place them into a grammar. A further embodiment of the invention provides a method and apparatus to identify names, personalities, titles, and topics that are not present in the repository, and place them into a grammar. A key aspect of the invention uses information from external data sources, notably non-speech, text-based searches, to expand the search terms entered into the ASR grammars. The expansion takes place in two forms: (1) finding plausible linguistic variants of existing search terms that are already comprehended in the repository, but that are under slightly different names; and (2) expanding the existing search term list with items that should be there by virtue of their currency in popular culture, but which for whatever reason have not yet been reflected with content items in the repository.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block schematic diagram showing search term generation flow according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The presently preferred embodiment of the invention provides a method and apparatus to identify names, personalities, titles, and topics that are present in a repository, and place them into a grammar. A further embodiment of the invention provides a method and apparatus to identify names, personalities, titles, and topics that are not present in the repository, and place them into a grammar. A key aspect of the invention uses information from external data sources, notably non-speech, text-based searches, to expand the search terms entered into the ASR grammars. The expansion takes place in two forms: (1) finding plausible linguistic variants of existing search terms that are already comprehended in the repository, but that are present under slightly different names; and (2) expanding the existing search term list with items that should be there by virtue of their currency in popular culture, but which for whatever reason have not yet been reflected with content items in the repository.

An exemplary embodiment of the invention operates as follows:

First, extract search term candidates, also referred to as candidate search terms, from external sources, for instance:

1. Published lists of frequent textual searches against popular search engines, e.g. Yahoo “top searches;”

2. Published lists of popular artists and songs, e.g. music.aol.com/songs/newsongs “Top 100 Songs;”

3. Published lists of popular tags, e.g. ETonline.com “top tags;”

4. Published lists of most-emailed stories, e.g. NYtimes.com most emailed stories, ETonline.com most emailed stories; and

5. Published news feeds, such as RSS feeds, e.g. NYtimes.com/rss.

Nominally for the first three sources listed above, the candidate search terms are clearly identified as an explicitly marked title, author, artist name, etc. and, hence, processing is purely automatic. For the final two sources listed above, a combination of automatic means, such as named entity extraction (NEE) and/or topic detection and tracking (TDT) methods, and possibly direct human intervention, are applied to the running text or titles to generate candidate search terms. However, human intervention may be used with the first group as well.

Next, extract verified search terms from internal sources, for instance:

1. Explicitly marked titles, authors, artist names, etc. that are associated to the content elements in the repository; and/or

2. Sources derived by application of named entity extraction (NEE) and/or topic detection and tracking (TDT) methods to descriptive text associated to the content elements in the repository.

Examples

-   -   Use of the topic “California fires”, appearing as the         tenth-most-popular searched item, as listed in the “MOST POPULAR         SEARCHED” section of the website www.nytimes.com of Oct. 27,         2007.     -   Extraction of the proper name “David Brooks” from the frequently         emailed article title “David Brooks: The Outsourced Brain,”         appearing as the second-most-popular emailed article, as listed         in the “MOST POPULAR EMAILED” section of the website         www.nvtimes.com of Oct. 27, 2007.

In the presently preferred embodiment of the invention, typical (although not exclusive) means of NEE and TDT analysis may be found in:

-   -   Foundations of Statistical Natural Language Processing, by Chris         Manning and Hinrich Schütze, MIT Press. Cambridge, MA: May 1999.     -   Proceedings of the DARPA Broadcast News Transcription and         Understanding Workshop, Feb. 8-11, 1998, Lansdowne Conference         Resort, Lansdowne, Va., available at URL http://www. n         ist.gov/speech/publications/darpa98/

Next, match candidate search terms against verified search terms by well-known edit distance techniques, to obtain plausible linguistic variants of verified search terms, used to generate the augmented verified search terms.

-   -   Example: “Mary J. Blige” is initial verified search term,         augmented with “Mary Blige” as a variant.

Finally, by virtue of their high incidence count, repeated appearance in history as either a candidate or verified search term, or other criterion, include in the grammar candidate search terms which do not point to actual content elements, but which the ASR system should nevertheless recognize. We refer to such elements as “null search terms.”

FIG. 2 is a block schematic diagram showing search term generation flow according to the invention.

In FIG. 1, a grammar is augmented with regard to external sources 11 and internal sources, e.g. the repository, both as discussed above.

External sources comprise, for example, explicitly marked information 12 and running text 15. Explicitly marked text may be subject to an optional count filtering process 14, providing incidence count information is available, whereby only those instances with sufficiently high incidence count are retained, while running text is processed, as discussed above, with a module 17 that performs, for example, named entity extraction (NEE) or topic detection and tracking (TDT). The data from all external sources is combined by a module 18 and an output, comprising candidate search terms (C[i])19 is generated. The combined output from external sources is further processed by a module 22 that performs such functions as incidence counting, low pass filtering, and other functions as desired, and is also passed to an approximate text matching module 33 (discussed below). This module 22 also receives historical information, such as a history of candidate search terms (C[i−1]. . . ) 20, a history of final search terms (S[i−1]. . . ) 21, and verified search terms (discussed in greater detail below). The output of the module 22 is provided to a further module 23, which identifies null search terms (N[i]), as discussed above.

Internal sources comprise, for example, explicitly marked information 27 and running text 28. Explicitly marked text may be subject to an optional count filtering process 29, whereby only those instances with sufficiently high incidence count are retained, while running text is processed, as discussed above, with a module 30 that performs, for example, named entity extraction (NEE) or topic detection and tracking (TDT). The data from all internal sources is combined by a module 31 and an output, comprising verified search terms (V[i]) 32 is generated. The verified search terms are used in connection with the module 22, as discussed above. The verified search terms are also provided to a module 33 for approximate text matching. The module 33 also receives candidate search terms from the module 19 as an input. The output of the module 33 is provided to a module 34 that generates augmented verified search terms (AV[i]).

The processed external sources information that is output by the module 23 and the processed internal sources information that is output by the module 34 are provided as inputs to a combining module 34 to produce final search terms (S[i]) 25, which are output for grammar generation.

Although the invention is described herein with reference to the preferred embodiment, one skilled in the art will readily appreciate that other applications may be substituted for those set forth herein without departing from the spirit and scope of the present invention. Accordingly, the invention should only be limited by the Claims included below. 

1. A method for identifying names, personalities, titles, and topics that may or may not be present in a repository and for placing them into a grammar, comprising the steps of: using information from external data sources comprising non-speech, text-based searches to expand search terms entered into one or more automatic speech recognition ASR grammars; said search terms expansion comprising any of: finding plausible linguistic variants of existing search terms that are already comprehended in the repository, but that are under slightly different names; and expanding an existing search term list with items that should be in said list by virtue of their currency in popular culture, but which for whatever reason have not yet been reflected with content items in the repository.
 2. A method for identifying names, personalities, titles, and topics that may or may not be present in a repository and for placing them into a grammar for use in an automatic speech recognition (ASR) system, comprising the steps of: extracting search term candidates from external sources; extracting verified search terms from internal sources; matching candidate search terms against verified search terms by edit distance techniques to obtain plausible linguistic variants of verified search terms; using said linguistic variants to generate augmented verified search terms; and including candidate search terms which do not point to actual content elements, but which the ASR system should nevertheless recognize, as null search terms in a final grammar by virtue of any of their high incidence count, repeated appearance in history as either a candidate or verified search term, or other criterion.
 3. The method of claim 2, said external sources comprising any of: published lists of frequent textual searches against popular search engines; published lists of popular artists and songs; and published lists of popular tags; wherein candidate search terms are clearly identified as an explicitly marked title, author, artist name, etc. and, hence, processing is automatic; and wherein human intervention is optionally used.
 4. The method of claim 2, said external sources comprising any of: published lists of most-emailed stories; and published news feeds; wherein a combination of automatic means, comprising either of named entity extraction (NEE) and/or topic detection and tracking (TDT) methods and direct human intervention are applied to running text or titles to generate candidate search terms.
 5. The method of claim 2, said internal sources comprising any of: explicitly marked titles, authors, artist names, etc. that are associated to content elements in said repository; and sources obtained by application of named entity extraction (NEE) and/or topic detection and tracking (TDT) methods to descriptive text associated to content elements in said repository.
 6. An apparatus for identifying names, personalities, titles, and topics that may or may not be present in a repository and for placing them into a grammar for use in an automatic speech recognition (ASR) system, comprising: a repository comprising external sources and internal sources; a module for combining data from all external sources and for generating an output comprising candidate search terms; a module for processing said candidate search terms by performing any of incidence counting, low pass filtering, and other functions; a module arranged to receive as inputs the output of said module for processing candidate search terms and historical information comprising any of a history of candidate search terms, a history of final search terms, and verified search terms, and for providing a processed external source output; a module for receiving the processed external source output, and for identifying and outputting null search terms; a module for combining data from all internal sources and for generating an output comprising said verified search terms; an approximate text matching module arranged to receive as inputs said verified search terms and said candidate search terms, and for providing an output; a module for receiving the output of said approximate text matching module and for providing an output comprising augmented verified search terms; a module for combining said null search terms with said augmented verified search terms and for outputting final search terms for grammar generation.
 7. The apparatus of claim 6, wherein said external sources comprise any of explicitly marked information and running text; said external sources comprising: an optional count filtering module for processing explicitly marked text, providing incidence count information is available, whereby only those instances with sufficiently high incidence count are retained; and a module for processing running text by performing any of named entity extraction (NEE) and topic detection and tracking (TDT).
 8. The apparatus of claim 6, wherein internal sources comprise any of explicitly marked information and running text; said internal sources comprising a module for processing running text by performing any of named entity extraction (NEE) and topic detection and tracking (TDT).
 9. An apparatus for identifying names, personalities, titles, and topics that may or may not be present in a repository and for placing them into a grammar, comprising: a plurality of external data sources, comprising non-speech, text-based searches; means for expanding search terms entered into one or more automatic speech recognition ASR grammars by using information from said external data sources, said means for expanding search terms comprising any of: means for finding plausible linguistic variants of existing search terms that are already comprehended in the repository, but that are under slightly different names; and means for expanding an existing search term list with items that should be in said list by virtue of their currency in popular culture, but which for whatever reason have not yet been reflected with content items in the repository.
 10. The apparatus of claim 9, further comprising: means for extracting search term candidates from said external sources; means for extracting verified search terms from said internal sources; means for matching candidate search terms against verified search terms by edit distance techniques to obtain plausible linguistic variants of verified search terms; means for using said linguistic variants to generate augmented verified search terms; and means for including candidate search terms which do not point to actual content elements, but which the ASR system should nevertheless recognize, as null search terms in a final grammar by virtue of any of their high incidence count, repeated appearance in history as either a candidate or verified search term, or other criterion.
 11. The apparatus of claim 10, said external sources comprising any of: published lists of frequent textual searches against popular search engines; published lists of popular artists and songs; and published lists of popular tags; wherein candidate search terms are clearly identified as an explicitly marked title, author, artist name, etc. and, hence, processing is automatic; and wherein human intervention is optionally used.
 12. The apparatus of claim 10, said external sources comprising any of: published lists of most-emailed stories; and published news feeds; wherein a combination of automatic means, comprising either of named entity extraction (NEE) and/or topic detection and tracking (TDT) methods and direct human intervention are applied to running text or titles to generate candidate search terms.
 13. The apparatus of claim 10, said internal sources comprising any of: explicitly marked titles, authors, artist names, etc. that are associated to content elements in said repository; and sources obtained by application of named entity extraction (NEE) and/or topic detection and tracking (TDT) methods to descriptive text associated to content elements in said repository.
 14. A method for identifying names, personalities, titles, and topics that may or may not be present in a repository and for placing them into a grammar for use in an automatic speech recognition (ASR) system, comprising the steps of: providing a repository comprising said external sources and internal sources; combining data from all external sources and generating candidate search terms; processing said candidate search terms by performing any of incidence counting, low pass filtering, and other functions; receiving said processed candidate search terms and historical information comprising any of a history of candidate search terms, a history of final search terms, and verified search terms, and providing a processed external source output; receiving the processed external source output, and identifying and outputting null search terms; combining data from all internal sources and generating said verified search terms; receiving said verified search terms and said candidate search terms and providing an approximate text matching output; receiving said approximate text matching output and outputting augmented verified search terms; combining said null search terms with said augmented verified search terms and outputting final search terms for grammar generation.
 15. The method of claim 14, wherein said external sources comprise any of explicitly marked information and running text; said external sources subject to a process comprising the steps of: processing explicitly marked text with an optional count filtering module providing incidence count information is available, whereby only those instances with sufficiently high incidence count are retained; and processing running text by performing any of named entity extraction (NEE) and topic detection and tracking (TDT).
 16. The method of claim 14, wherein internal sources comprise any of explicitly marked information and running text; and further comprising the step of processing running text by performing any of named entity extraction (NEE) and topic detection and tracking (TDT). 